The present invention is directed toward a respiration monitoring device and more particularly toward such a device which is utilized to monitor an infant's breathing while the patient is sleeping.
Infant apnea syndrome, the new name for near-miss SIDS, characterizes infants between 42 weeks gestational age and 12 months chronological age who experience clinically significant apneas having a duration of 10 seconds or more. Documentation of this phenomenon is generally obtained during polysomnographic recording sessions while the subject sleeps. During cardio-respiratory assessment, a major difficulty is the inability to track airflow continuously and reliably over prolonged periods of time.
Heat resistant thermistors are widely used to detect airflow from the nose and mouth and function by sensing ambient temperature changes proximal to them. Thermistors are more advantageous than other devices for qualitative airflow analysis because of their small size and rapid responsiveness. However, difficulties have been experienced, particularly with infants, in maintaining the thermistors in their proper position.
Several devices have been proposed in the past which are intended to be worn by a subject in order to position the thermistors. Examples of these are shown in U.S. Pat. Nos. 2,831,181; 3,232,288 and 3,241,549. These devices, however, are intended primarily for adult subjects and do not readily lend themselves to use with sleeping infants. The writhing and other movements of the infant during sleep tend to dislodge these devices and can also create artifacts and false readings.
In order to overcome the problems of the prior art devices which include harnesses or straps or the like for holding the thermistors in place, some investigators have attempted to simply tape the thermistors in place in order to detect nasal and oral airflow. Using this technique, however, it is difficult to properly align the various thermistors. Furthermore, even if an investigator succeeds in properly placing the thermistors, this is a time-consuming procedure which can be annoying to the infant. Even further, it is difficult to accurately reproduce the positions of the thermistors from day to day for a series of tests.